You have every right to be “a bit unscrupulous”. You’re paying for the service. By ignoring your perfectly reasonable request, she’s being very rude and selfish.
Suggestion: once you’ve found a solution, don’t tell her what you’ve done. If she complains about a slow connection, blame it on the ISP for throttling your service or something. I’d suggest blaming her computer, but that could backfire if she asks you to fix the damn thing.
This is one of the extremely rare instances where I can almost sympathize with the man. Making inflammatory statements is his whole shtick. It’s all he knows. To him, being told not to make inflammatory statements is like being told not to talk at all.
(Personally, I’d be perfectly happy if I never heard from him again, but that’s beside the point.)